Do My Supply Ducts Keep My Water Pipes From Freezing?

nerdyshopperDecember 18, 2012

Both my supply ducts and my water pipes run through a vented crawl space under my home. I live in Eastern Washington and outdoor temperatures normally run from zero to 20 degrees in the coldest part of winter. I plug the vents with foam plugs in Winter. My question is: Are the ducts keeping my water pipes from freezing. (Temperatures as low as 25 below have been known here). I have foam lagging on hot water pipes and use a recirculating pump because it takes about 7 minutes to get hot water to the kitchen otherwise. Is there someting I can do to make this system more energy efficient? I also have a problem with a hose bib that sometimes drips when on and fills one of the galvanized barriers for a vent that is under the hose bib.

ducts should be sealed to keep conditioned air
inside duct. ducts should be insulated to keep
temp of air in ducts close to supplied temp.
I can't see why, unless ducts are unsealed
& uninsulated, that ducts would affect the
water pipes at all.

more likely pipe insulation is what keeps
pipes from freezing.
what is foam lagging? tubular pipe insulation?

Thanks for the help. I haven't been in the crawl space to look at what is going on. I had a plumber lag the pipes with a foam lagging that is flexible and has a slit running the length of it. It clings to the pipe and is only taped at intervals. He told me it wouldn't keep the pipes from freezing eventually in a long cold snap. I had a recirculating pump installed on top of my hot water tank because it is a very long run to the kitchen from the garage where the tank is located. But my pipes have never frozen and so I was just wondering.
Thanks again.